The preparation of 3H-1,2-diazepine 2-oxides and their rearrangement to give 3-alkenyl-3H-pyrazole 2-oxides

4-Phenyl-6,7,8,9-tetrahydro-1H-2,3-benzodiazepine 2-oxide, C15H16N2O

“…The title compound (1) was prepared by oxidation of 4-phenyl-6,7,8,9-tetrahydro-lH-2,3-benzodiazepine (2) using m-chloroperbenzoic acid (m-CPBA) (Argo, Robertson & Sharp, 1984). The barrier to ring inversion in the diazepine ring of the oxide (1) is substantially reduced by about 15 kJ mo1-1 compared with the parent diazepine (2) as determined by variable-temperature 1H NMR studies.…”